With development of data storage technologies, various kinds of data storage devices already can provide a user with an increasingly high data storage capacity, and data access speed has also been greatly improved. Currently, several kinds of hard disk array-based data storage devices have been developed to enhance data reliability. A conventional storage device includes a chassis and a hard disk assembly that can be drawn out of and pushed into the chassis. When the user wants to extend the hard disk array in the hard disk assembly or replace a hard disk in the hard disk array, the hard disk drawer that bears the hard disk array needed to be drawn out of the chassis. In this case, a distance between a fan in the chassis and the hard disk assembly will be enlarged, which affects heat dissipation performance of the storage device.